Imaging lens

Abstract

The present invention relates to an imaging lens comprising a first lens group (G1) with positive or negative optical power, a stop (STOP), and a second lens group (G2) with positive optical power, arranged in sequence from the object side to the image side along the optical axis. The first lens group (G1) and the second lens group (G2) are relatively stationary and can move together along the optical axis. The imaging lens of the present invention has the characteristics of a large aperture, a large image surface, high resolution, good color reproduction, and high relative illumination.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to an imaging lens. Background Art

[0002] With the development of intelligent transportation systems, the market requirements for intelligent transportation lenses are becoming increasingly stringent. While some existing intelligent transportation lenses can achieve large apertures and large image areas, they generally struggle to balance image quality and relative illumination requirements, limiting the lens's usability. Summary of the Invention

[0003] The object of the present invention is to provide an imaging lens.

[0004] To achieve the above-mentioned objectives, the present invention provides an imaging lens, comprising a first lens group with positive or negative optical power, an aperture, and a second lens group with positive optical power, arranged in sequence from the object side to the image side along the optical axis. The first lens group and the second lens group are relatively stationary and can move together along the optical axis.

[0005] According to one aspect of the present invention, the first lens group includes five or six lenses, two or three of which are positive lenses and three are negative lenses.

[0006] According to one aspect of the present invention, in the first lens group, the first lens is a negative lens with a concave image-side surface; the second lens is a negative lens with a concave object-side surface; the third lens is a positive lens with a convex image-side surface; the fourth lens is a positive lens; and the last lens is a negative lens with a convex-concave shape.

[0007] According to one aspect of the present invention, the second lens group includes four or five lenses, three or four of which are positive lenses and one is a negative lens.

[0008] According to one aspect of the present invention, in the second lens group, the third lens is a positive lens with a convex-convex shape; the last lens is a positive lens with a convex object-side surface;

[0009] The side of the second lens group closest to the aperture has a cemented lens group.

[0010] According to one aspect of the present invention, the focal length value f2 of the second lens group and the focal length value f of the imaging lens satisfy the following relationship: 1.3≤f2 / f≤1.7.

[0011] According to one aspect of the present invention, the focal length value f2 of the second lens group and the focal length value f1 of the first lens group satisfy the following relationship: 0.05≤|f2 / f1|≤0.7.

[0012] According to one aspect of the present invention, the length L of the imaging lens and the target surface diameter φ satisfy the following relationship: 4.4≤L / φ≤5.0.

[0013] According to one aspect of the present invention, the Abbe number VD of at least one positive lens in the second lens group is Li and refractive index ND Li Meet the following conditions: 60≤VD Li ≤90; 1.4≤ND Li ≤1.6.

[0014] According to one aspect of the present invention, the relative refractive index temperature coefficient dn / dt of at least one positive lens in the second lens group is (Li) Meet the following conditions: -8*10 -6 ≤dn / dt (Li) ≤-3*10 -6 .

[0015] According to the solution of the present invention, an optical imaging lens with large aperture, large target area, high resolution, good color reproduction and high relative illumination is provided.

[0016] According to one embodiment of the present invention, the first lens group is used to correct the aberration and distortion of the system. The two groups are moved together along the optical axis to perform focusing, which can effectively reduce the tolerance sensitivity of the system, improve the imaging quality at different object distances, and ensure the uniformity of the picture.

[0017] According to one aspect of the present invention, by rationally matching the positive and negative lenses in the first lens group, spherical aberration, astigmatism, and distortion within the first lens group are corrected, facilitating the realization of a large aperture while also reducing sensitivity to intra-group tolerances. Furthermore, by rationally designing the concave and convex properties of each lens in the first lens group, the imaging lens can smoothly collect incident light, effectively reducing field curvature and astigmatism caused by incident light at wide field angles, achieving a large aperture while maintaining low distortion.

[0018] According to one aspect of the present invention, the rational combination of positive and negative lenses in the second lens group facilitates correction of spherical aberration, astigmatism, and distortion within the second lens group. Correcting aberrations within the second lens group reduces the burden of aberration correction on the first lens group, further reducing the group's sensitivity to tolerance and overall improving the imaging quality of the lens. Furthermore, rationally designing the concavity and convexity of each lens in the second lens group and utilizing cemented lens groups effectively reduce the imaging lens's sensitivity to tolerance and ensure sufficient optical back focus, thereby achieving a smaller principal ray incident angle and achieving higher color reproduction.

[0019] According to one embodiment of the present invention, by properly setting the relationship between the focal length of the second lens group and the focal length of the imaging lens, the optical power of the two groups can be effectively controlled to ensure a reasonable match, thereby reducing the tolerance sensitivity between the groups, which is beneficial to improving the imaging quality of the imaging lens and ensuring the uniformity of the image.

[0020] According to one embodiment of the present invention, by reasonably setting the relationship between the focal length of the second lens group and the focal length of the first lens group, the burden ratio of the two groups of the imaging lens in terms of back focus and CRA can be balanced, which is conducive to ensuring focusing performance and a smaller incident angle of the image plane principal ray, and can better improve the imaging quality of the imaging lens.

[0021] According to one solution of the present invention, by reasonably setting the relationship between the length of the imaging lens and the target surface diameter, the size of the large image surface lens can be constrained, which is conducive to reducing the lens volume, saving space and controlling costs.

[0022] According to one embodiment of the present invention, by ensuring that the Abbe number and refractive index of at least one positive lens in the second lens group meet specific conditions, the aberrations of the system can be effectively reduced, the chromatic aberration and distortion of the imaging lens can be corrected, and temperature correction of the system can be facilitated. At the same time, the incident angle of light can be controlled, and the sensitivity to tolerances can be reduced, thereby improving the imaging quality of the imaging lens.

[0023] According to one embodiment of the present invention, the relative refractive index temperature coefficient of at least one positive lens in the second lens group is made to meet certain conditions, which is beneficial to the temperature correction of the athermal system and can more effectively balance the image plane drift at the telephoto end of the imaging lens under high and low temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A diagram schematically showing the structure of an imaging lens according to a first embodiment of the present invention;

[0025] Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 Schematically showing an MTF diagram, a distortion diagram, a magnification chromatic aberration diagram, and a position chromatic aberration diagram of the imaging lens of the first embodiment of the present invention when focusing at the optimal working object distance;

[0026] Figure 6 A diagram schematically showing the structure of an imaging lens according to a second embodiment of the present invention;

[0027] Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 Schematically showing an MTF diagram, a distortion diagram, a magnification chromatic aberration diagram, and a position chromatic aberration diagram of the imaging lens of the second embodiment of the present invention when focusing at the optimal working object distance;

[0028] Figure 11 A diagram schematically showing the structure of an imaging lens according to a third embodiment of the present invention;

[0029] Figure 12 、 Figure 13 、 Figure 14 、 Figure 15 Schematically showing an MTF diagram, a distortion diagram, a magnification chromatic aberration diagram, and a position chromatic aberration diagram of the imaging lens of the third embodiment of the present invention when focusing at the optimal working object distance;

[0030] Figure 16 A diagram schematically showing the structure of an imaging lens according to a fourth embodiment of the present invention;

[0031] Figure 17 、 Figure 18 、 Figure 19 、 Figure 20 Schematically showing an MTF diagram, a distortion diagram, a magnification chromatic aberration diagram, and a position chromatic aberration diagram of the imaging lens of the fourth embodiment of the present invention when focusing at the optimal working object distance;

[0032] Figure 21 A diagram schematically showing the structure of an imaging lens according to a fifth embodiment of the present invention;

[0033] Figure 22 、 Figure 23 、 Figure 24 、 Figure 25 The MTF diagram, distortion diagram, magnification chromatic aberration diagram, and position chromatic aberration diagram of the imaging lens of the fifth embodiment of the present invention when focusing at the optimal working object distance are schematically shown respectively. DETAILED DESCRIPTION

[0034] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0035] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0036] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0037] See also Figure 1 The imaging lens of the present invention is an intelligent traffic lens, comprising a first lens group G1 with positive or negative focal power, an aperture STOP, and a second lens group G2 with positive focal power, arranged sequentially along the optical axis from the object side to the image side. The first lens group G1 and the second lens group G2 are relatively stationary and can move together along the optical axis to achieve focusing at different object distances. The first lens group G1 primarily corrects for system aberrations and distortion. Using the two lens groups to move together along the optical axis for focusing effectively reduces the system's tolerance sensitivity, improves imaging quality at different object distances, and ensures image uniformity.

[0038] In the present invention, the first lens group G1 includes five or six lenses, of which two or three are positive lenses and three are negative lenses. The combination of the optical power of positive and negative lenses is beneficial for correcting the spherical aberration, astigmatism and distortion within the first lens group G1, which is beneficial for achieving a large aperture, and can also reduce the sensitivity of tolerances within the group. In the first lens group G1, the first lens is a negative lens with a concave image side; the second lens is a negative lens with a concave object side; the third lens is a positive lens with a convex image side; the fourth lens is a positive lens; and the last lens is a negative lens with a convex-concave shape. By meeting the above settings, the imaging lens can smoothly collect incident light, effectively reduce the field curvature and astigmatism generated by incident light with a large field of view angle, and maintain low distortion while achieving a large aperture.

[0039] In the present invention, the second lens group G2 includes four or five lenses, three or four of which are positive lenses and one is a negative lens. The combination of the optical power of the positive and negative lenses and the use of cemented sheets are beneficial for correcting spherical aberration, astigmatism, and distortion within the second lens group G2. The correction of the aberrations within the second group is also beneficial for reducing the proportion of the burden of aberration correction on the first lens group, which can better reduce the tolerance sensitivity of the group and comprehensively improve the imaging quality of the imaging lens. In the second lens group G2, the third lens is a positive lens with a convex-convex shape; the last lens is a positive lens with a convex object side. The second lens group G2 has a cemented lens group on the side closest to the aperture STOP. Meeting the above settings can effectively reduce the tolerance sensitivity of the imaging lens and ensure sufficient optical back focus, which is beneficial for achieving a smaller principal ray incident angle and achieving higher image color reproduction.

[0040] In the present invention, the focal length f2 of the second lens group G2 and the focal length f of the imaging lens satisfy the following relationship: 1.3 ≤ f2 / f ≤ 1.7. This relationship effectively controls the focal power of the two lens groups, ensuring a reasonable match and reducing sensitivity to tolerances between the groups. This improves the imaging quality of the imaging lens and ensures image uniformity.

[0041] In the present invention, the focal length f2 of the second lens group G2 and the focal length f1 of the first lens group G1 satisfy the following relationship: 0.05 ≤ |f2 / f1| ≤ 0.7. This relationship balances the back focus and CRA burdens of the two lens groups, ensuring optimal focusing performance and minimizing the incident angle of the principal ray on the image plane, thereby enhancing the image quality of the lens.

[0042] In the present invention, the length L of the imaging lens (total length at infinite object distance) and the target diameter φ satisfy the following relationship: 4.4 ≤ L / φ ≤ 5.0. Satisfying this relationship constrains the size of large image lenses, helping to reduce lens volume, saving space while controlling costs.

[0043] In the present invention, the Abbe number VD of at least one positive lens in the second lens group G2 is Li and refractive index ND Li Satisfy the following relationship: 60≤VD Li ≤90; 1.4≤ND Li ≤1.6. Meeting the above relationship can effectively reduce the system's aberration, correct the chromatic aberration and distortion of the imaging lens, facilitate the system's temperature correction, and simultaneously control the incident angle of light, reducing the sensitivity of tolerances, thereby improving the imaging quality of the imaging lens.

[0044] In the present invention, the relative refractive index temperature coefficient dn / dt of at least one positive lens in the second lens group G2 is (Li) Meet the following conditions: -8*10 -6 ≤dn / dt (Li) ≤-3*10 -6 Satisfying the above relationship is beneficial to the temperature correction of the athermal system and can more effectively balance the image plane drift of the imaging lens at the telephoto end under high and low temperature conditions.

[0045] In summary, the imaging lens of the present invention adopts a global glass structure, with a reasonable distribution of anomalous dispersion glass and high refractive index glass, which can achieve high-quality imaging effects with low cost and high performance. The lens aperture of the present invention can reach 1.1, so that the lens can have sufficient light intake and obtain clearer images. In addition, by reasonably matching positive and negative optical focal length lenses, high image quality performance can be achieved at different object distances, which is beneficial to the correction of temperature drift at high and low temperatures. The optical focal length of the two groups is effectively controlled. The lenses are reasonably matched to reduce the tolerance sensitivity between groups, which is beneficial to improving the imaging quality of the imaging lens and ensuring the uniformity of the picture. In addition, by reasonably using cemented lenses, it is beneficial to correct the chromatic aberration and spherical aberration of the entire imaging lens.

[0046] The imaging lens of the present invention is described in detail below using five sets of embodiments. In the following embodiments, sur1, sur2, ..., surN are used to represent the surfaces of each lens, the aperture is denoted as Stop, and the image plane is denoted as Image.

[0047] Parameters of various implementations that specifically meet the above conditional formula are as follows:

[0048]

[0049] Table 1

[0050] First implementation method

[0051] See also Figure 1 In this embodiment, the first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. The second lens group G2 includes a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and an eleventh lens L11. The seventh lens L7, the eighth lens L8, and the ninth lens L9 are cemented together to form a cemented triplet. The system has an effective focal length of f = 25.73 mm, an aperture FNO = 1.1, and a total system length TTL = 103.59 mm (total length at object distance infinity).

[0052] The refractive index Nd of the first lens in the second lens group G2 (i.e., the seventh lens L7) L7 and Abbe number Vd L7 Nd L7 =1.49; Vd L7 =60.6, relative refractive index temperature coefficient dn / dt (L7) =dn / dt (L7) =-5.7*10 -6 The refractive index Nd of the fourth lens (i.e., the tenth lens L10) in the second lens group G2 is L10 and Abbe number Vd L10 Nd L10=1.50; Vd L10 =81.6, relative refractive index temperature coefficient dn / dt (L10) =dn / dt (L10) =-6.2*10 -6 .

[0053] The parameters of each lens of the imaging lens of this embodiment are shown in Table 2 below:

[0054] # Type Radius Thickness nd vd sur1 standard -201.566 1.10 1.81 22.8 sur2 standard 35.256 9.85 sur3 standard -31.025 5.56 1.70 30.1 sur4 standard -468.268 1.35 sur5 standard -132.275 6.34 1.77 49.6 sur6 standard -42.584 0.10 sur7 standard 113.548 7.00 1.83 42.7 sur8 standard -68.56 0.78 sur9 standard 46.18 4.46 1.95 18.0 sur10 standard 94.817 10.50 sur11 standard 30.358 4.37 1.70 30.1 sur12 standard 24.639 8.04 Stop standard infinity 5.34 sur14 standard -45.368 4.95 1.49 60.6 sur15 standard -19.584 1.24 1.85 23.8 sur16 standard 38.592 6.72 1.70 55.5 sur17 standard -40.026 0.58 sur18 standard 63.586 6.38 1.50 81.6 sur19 standard -38.946 4.81 sur20 standard 48.591 5.86 1.95 18.0 sur21 standard 96.458 8.26 Image

[0055] Table 2

[0056] Combine Figures 2 to 5 As can be seen, the imaging lens of this embodiment utilizes an all-glass structure with a rational distribution of anomalous dispersion glass and high-refractive index glass, achieving high-quality imaging at a low cost. The lens boasts an aperture of up to 1.1, allowing ample light to enter the lens for clearer images. The rational combination of positive and negative power lenses ensures high image quality at varying object distances and facilitates correction of temperature drift at high and low temperatures, as well as chromatic and spherical aberrations of the entire optical system.

[0057] Second implementation method

[0058] See also Figure 6 In this embodiment, the first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. The second lens group G2 includes a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and an eleventh lens L11. The seventh lens L7 and the eighth lens L8 are cemented together to form a doublet. The system has an effective focal length of f = 28.195 mm, an aperture FNO = 1.2, and a total system length TTL = 100.49 mm (total length at object distance infinity).

[0059] The refractive index Nd of the second lens in the second lens group G2 (i.e., the eighth lens L8) L8 and Abbe number Vd L8 Nd L8 =1.45; Vd L8 =85, relative refractive index temperature coefficient dn / dt (L8) =dn / dt (L8) =-5.7*10 -6 .

[0060] The parameters of each lens of the imaging lens of this embodiment are shown in Table 3 below:

[0061]

[0062]

[0063] Table 3

[0064] Combine Figures 7 to 10 As can be seen, the imaging lens of this embodiment utilizes an all-glass structure with a rational distribution of anomalous dispersion glass and high-refractive index glass, achieving high-quality imaging at a low cost. The lens boasts an aperture of up to 1.1, allowing ample light to enter the lens for clearer images. The rational combination of positive and negative power lenses ensures high image quality at varying object distances and facilitates correction of temperature drift at high and low temperatures, as well as chromatic and spherical aberrations of the entire optical system.

[0065] Third implementation method

[0066] See also Figure 11 In this embodiment, the first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. The second lens group G2 includes a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, and a tenth lens L10. Sixth lens L6 and seventh lens L7 are cemented together to form a doublet. The system has an effective focal length of f = 23.29 mm, an aperture FNO = 1.14, and a total system length TTL = 100.53 mm (total length at object distance infinity).

[0067] The refractive index Nd of the second lens in the second lens group G2 (i.e., the seventh lens L7) L7 and Abbe number Vd L7 Nd L7 =1.59; Vd L7 =68.6, relative refractive index temperature coefficient dn / dt (L7) =dn / dt (L7) =-5.7*10 -6 .

[0068] The parameters of each lens of the imaging lens of this embodiment are shown in Table 4 below:

[0069]

[0070]

[0071] Table 4

[0072] Combine Figures 12 to 15As can be seen, the imaging lens of this embodiment utilizes an all-glass structure with a rational distribution of anomalous dispersion glass and high-refractive index glass, achieving high-quality imaging at a low cost. The lens boasts an aperture of up to 1.1, allowing ample light to enter the lens for clearer images. The rational combination of positive and negative power lenses ensures high image quality at varying object distances and facilitates correction of temperature drift at high and low temperatures, as well as chromatic and spherical aberrations of the entire optical system.

[0073] Fourth implementation method

[0074] See also Figure 16 In this embodiment, the first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. The second lens group G2 includes a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and an eleventh lens L11. The seventh lens L7 and the eighth lens L8 are cemented together to form a doublet. The system has an effective focal length f = 22.4 mm, an aperture FNO = 1.05, and a total system length TTL = 111.19 mm (total length at object distance infinity).

[0075] The refractive index Nd of the first lens in the second lens group G2 (i.e., the seventh lens L7) L7 and Abbe number Vd L7 Nd L7 =1.50; Vd L7 =81.6, relative refractive index temperature coefficient dn / dt (L7) =dn / dt (L7) =-5.7*10 -6 The refractive index Nd of the fourth lens (i.e., the tenth lens L10) in the second lens group G2 is L10 and Abbe number Vd L10 Nd L10 =1.59; Vd L10 =68.6, relative refractive index temperature coefficient dn / dt (L10) =dn / dt (L10) =-6.2*10 -6 .

[0076] The parameters of each lens of the imaging lens of this embodiment are shown in Table 5 below:

[0077] # Type Radius Thickness nd Vd sur1 standard 275.395 4.46 1.86 44.1 sur2 standard 34.569 10.04 sur3 standard -27.482 7.02 1.72 47.0 sur4 standard -510.614 1.38 sur5 standard -128.591 5.95 1.78 55.4 sur6 standard -38.641 0.10 sur7 standard -211.761 3.60 1.88 25.0 Stop standard -68.512 0.10 sur9 standard 43.775 6.02 1.97 27.5 sur10 standard 204.951 9.25 sur11 standard 70.561 3.00 1.70 30.1 sur12 standard 21.178 7.12 sur13 standard infinity 4.30 sur14 standard -69.541 7.80 1.50 81.6 sur15 standard -16.512 1.82 1.85 47.5 sur16 standard -201.128 1.00 sur17 standard 90.751 5.94 1.62 63.4 sur18 standard -39.621 0.21 sur19 standard 61.175 6.38 1.59 68.6 sur20 standard -36.566 1.48 sur21 standard 45.631 5.99 1.92 18.4 sur22 standard 83.451 18.23 Image

[0078] Table 5

[0079] Combine Figures 17 to 20As can be seen, the imaging lens of this embodiment utilizes an all-glass structure with a rational distribution of anomalous dispersion glass and high-refractive index glass, achieving high-quality imaging at a low cost. The lens boasts an aperture of up to 1.1, allowing ample light to enter the lens for clearer images. The rational combination of positive and negative power lenses ensures high image quality at varying object distances and facilitates correction of temperature drift at high and low temperatures, as well as chromatic and spherical aberrations of the entire optical system.

[0080] Fifth implementation method

[0081] See also Figure 21 In this embodiment, the first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. The second lens group G2 includes a seventh lens L7, an eighth lens L8, a ninth lens L9, and a tenth lens L10. The seventh lens L7, the eighth lens L8, and the ninth lens L9 are cemented together to form a cemented triplet. The system has an effective focal length of f = 27.95 mm, an aperture FNO = 1.2, and a total system length TTL = 110.4 mm (total length at object distance infinity).

[0082] The refractive index Nd of the second lens in the second lens group G2 (i.e., the eighth lens L8) L8 and Abbe number Vd L8 Nd L8 =1.44; Vd L8 =95.1, relative refractive index temperature coefficient dn / dt (L8) =dn / dt (L8) =-6.8*10 -6 .

[0083] The parameters of each lens of the imaging lens of this embodiment are shown in Table 6 below:

[0084]

[0085]

[0086] Table 6

[0087] Combine Figures 22 to 25 As can be seen, the imaging lens of this embodiment utilizes an all-glass structure with a rational distribution of anomalous dispersion glass and high-refractive index glass, achieving high-quality imaging at a low cost. The lens boasts an aperture of up to 1.1, allowing ample light to enter the lens for clearer images. The rational combination of positive and negative power lenses ensures high image quality at varying object distances and facilitates correction of temperature drift at high and low temperatures, as well as chromatic and spherical aberrations of the entire optical system.

[0088] The above description is merely one embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An imaging lens comprising two lens groups, namely, a first lens group (G1) with positive or negative optical power, a stop (STOP), and a second lens group (G2) with positive optical power, arranged in sequence from the object side to the image side along the optical axis, wherein: The first lens group (G1) and the second lens group (G2) are relatively stationary and can move together along the optical axis; The first lens group (G1) includes only five or six lenses, three of which are negative lenses and the remaining two or three are positive lenses; in the first lens group (G1), the first lens is a negative lens, the second lens is a negative lens, the third lens is a positive lens, the fourth lens is a positive lens, and the last lens is a negative lens; When the first lens group (G1) includes only five lenses, the second lens group (G2) includes only five lenses, the first lens of the second lens group (G2) is a negative lens, and the remaining four lenses are positive lenses; Alternatively, when the first lens group (G1) includes only six lenses, the second lens group (G2) includes only five lenses, the first lens or the second lens of the second lens group (G2) is a negative lens, and the remaining four lenses are positive lenses; Alternatively, when the first lens group (G1) includes only six lenses, the second lens group (G2) includes only four lenses, the second lens of the second lens group (G2) is a negative lens, and the remaining four lenses are positive lenses.

2. The imaging lens according to claim 1, wherein: In the first lens group (G1), the image side surface of the first lens is concave; the object side surface of the second lens is concave; the image side surface of the third lens is convex; and the shape of the last lens is convex-concave.

3. The imaging lens according to claim 1, wherein: In the second lens group (G2), the third lens is convex-convex; the object side surface of the last lens is convex; When the first lens group (G1) includes only six lenses, the second lens group (G2) includes only five lenses, and the second lens of the second lens group (G2) is negative, the first lens, the second lens, and the third lens of the second lens group (G2) are cemented to form a triplet lens, or the first lens and the second lens of the second lens group (G2) form a doublet lens; Alternatively, when the first lens group (G1) includes only six lenses and the second lens group (G2) includes only five lenses, and the first lens of the second lens group (G2) is negative, the first lens and the second lens of the second lens group (G2) are cemented to form a doublet lens; Alternatively, when the first lens group (G1) includes only five lenses and the second lens group (G2) includes only five lenses, the first lens and the second lens of the second lens group (G2) are cemented to form a cemented lens; Alternatively, when the first lens group (G1) includes only six lenses and the second lens group (G2) includes only four lenses, the first lens, the second lens and the third lens of the second lens group (G2) are cemented to form a triplet lens.

4. The imaging lens according to any one of claims 1 to 3, wherein: The focal length value f2 of the second lens group (G2) and the focal length value f of the imaging lens satisfy the following relationship: 1.3≤f2 / f≤1.

7.

5. The imaging lens according to any one of claims 1 to 3, wherein: The focal length value f2 of the second lens group (G2) and the focal length value f1 of the first lens group (G1) satisfy the following relationship: 0.05≤|f2 / f1|≤0.

7.

6. The imaging lens according to any one of claims 1 to 3, wherein: The length L of the imaging lens and the target surface diameter φ satisfy the following relationship: 4.4≤L / φ≤5.

0.

7. The imaging lens according to claim 3, wherein: The Abbe number VD of at least one positive lens in the second lens group (G2) is Li and refractive index ND Li Meet the following conditions: 60≤VD Li ≤90; 1.4≤ND Li ≤1.6。 8. The imaging lens according to claim 3, wherein: The relative refractive index temperature coefficient dn / dt of at least one positive lens in the second lens group (G2) is (Li) Meet the following conditions: -8*10 -6 ≤dn / dt (Li) ≤-3*10 -6 .

Images